Re: TI-85 and log(-4)


[Prev][Next][Index][Thread]

Re: TI-85 and log(-4)



On Thu, 24 Jul 1997 18:56:52 GMT, David Socher wrote to Calc-TI:
>
> My algebra instructor had everyone punch the log of a negative number
> into their calculator to demonstrate that this could not be done.

What can and can't be done always depends on what you're trying to do it
with, as you saw...

> Everyone got an error message except me and my TI-85.  I got something
> that looks like a complex number.

Bingo!  This is what you got, assuming modes of RectC and Fix 4:

 (Fake TI-85 Screen)
|--------------------|
|log -4              |
|      (.6021,1.3644)|  <--- This is the "rectangular" format for a
|                    |       complex number.  The first number is the
|                    |       real part, and the second number is the
|                    |       imaginary part, where i=sqrt(-1).
|                    |       Anytime you see this, until you take
|                    |       advanced algebra, analysis, pre-calculus,
|                    |       or whatever they call it in your school,
|--------------------|       your classmates are getting error messages.

> The manual doesn't to cover it.

See pages 11-2 through 11-4 regarding complex numbers, their format, and
the functions and commands for complex math.

Hope this helps!


Jason T. Selkowitz


*************************Jason T. Selkowitz***************************
* 16532 NE 36th Ct. LL202  * mailto:selkowtz@u.washington.edu        *
* Redmond, WA  98052-6364  * http://weber.u.washington.edu/~selkowtz *
**********************************************************************


References: